I need solution for problem 5 A party is attended by n great

I need solution for problem 5.

A party is attended by n greaterthanorequalto 2 people. there will always be two people in attendance who have the same number of friends at the party. (Assume that the relation is a friend of is symmetric, that is, if a; is a friend of y then y is a friend of x.) Please provide a rephrasing of the above problem in terms of n points on the plane and colorings of the edges that connect these n points.

Solution

Let G be a coplete graph wih n vertice, with a vertice representing attendee. (n > = 2).

Edges in G are colored blue if attendees are freinds and red if they are not.

Then there wil always be two vertices with equal number of blue edges from them.